Field of the Invention
The present invention relates to an electrophotographic apparatus, more particularly, an electrophotographic apparatus for exposing and scanning a document placed on a fixed copy board by a scanning optical system.
In a prior electrophotographic apparatus there is used a copy board moving system for exposing and scanning a document placed on a moving copy board and an optical system scanning method for exposing and scanning a document placed on a fixed copy board by a moving optical system. The electrophotographic apparatus adopting the former system has a small size and a low price. The electrophotographic apparatus adopting the latter system has a comparatively large size and a high price, but has good operation because of use of the fixed copy board and a possibility of high speed copying.
The document to be copied can be classified into the following groups, i.e., a book and a sheet-like document. The book is understood herein to be all kinds of literature and bound reports which have a certain thickness and the sheet-like document is understood to be a document for business use. The documents to be copied are almost all sheet-like documents rather than a book.
In order to efficiently copy the sheet-like document it is preferable to expose and scan the document while moving it by feed rollers. The type of the electrophotographic apparatus comprising such a mechanism, i.e., a sheet feed device, is almost non-existent, (a) the electrophotographic apparatus which can also copy the thick document such as a book becomes high priced if the sheet feed device exclusively for the sheet-like document is added to the apparatus, (b) it is impossible to provide the sheet feed device as it is to the electrophotographic apparatus adopting the optical system scanning method having the fixed copy board, (c) it is difficult to realize the sheet feed device required to feed the document with stability according to the paper quality of the sheet-like document which varies in wide range, (d) when a multiple copies are obtained from the same document, it is not efficient because the document must repeatedly be fed the required number of times by necessary numbers, (e) the electrophotographic apparatus comprising an automatic collating device can not fully provide the function of the sorter in connection with the case of the item (d).
The problems of items (d) and (e) can be resolved by using the electrophotographic apparatus having storage capability for information in the document, i.e., the electrophotographic apparatus which can obtain a plurality of copies based on an image-like modulated information formed by only one exposure.
An object of the present invention is to eliminate the above disadvantages of the conventional electrophotographic device.
Another object of the present invention is to provide an electrophotographic apparatus in which mechanisms capable of effectively copying a sheet-like document and capable of copying a thick document such as a book are provided to the electrophotographic apparatus adopting an optical system scanning method with a fixed copy board.